“The Sounds of Thunder” is an okay episode of Star Trek: Discovery. Kaminar, the home world of Saru (Doug Jones), is a nifty setting, with a fragile ecosystem split between diametrically opposed species. The Ba’ul are faceless techno-freaks who rule with advanced weaponry and omniscient surveillance devices. Saru’s race, the Kelpians, are super-chill, earthy spiritualists tending peaceful gardens near crimson-sanded coastal real estate.

It is a planet split between, like, hippies from Humboldt and the most tyrannical paranoid fantasy of Silicon Valley broverlords. And “Sounds of Thunder” goes the extra half-mile to complicate our understanding of this dynamic. In the distant past, Ba’ul were nearly hunted to extinction by tyrannical Kelpians. That near-genocide sparked the Ba’ul toward technological advancement — and transformed them into the cruel overseers, culling Kelpians for whole eons of history behind record.

The episode, written by Bo Yeon Kim and Erika Lippoldt, also benefits from the focus on Saru. Jones’ performance exudes low-key whimsy on a TV series that’s full of uber-dramatic aggro action. His return home has moments of poignance. Absent for 18 years after mysteriously disappearing into the sky, he discovers his beloved sister, Siranna (Hannah Spear), is now a local priest. (His father is dead, culled by the Ba’ul.) He dreams of inspiring his people toward revolution — but that runs against the orders of Captain Pike (Anson Mount) and trips over certain semantics in the Prime Directive. So the main character and the main setting are both torn in two directions: cool!

But Saru is experiencing personality changes after the loss of his threat ganglia. And the only thing more unfortunate than the phrase “threat ganglia” is that Saru’s new personality manifests with Uber-Dramatic Aggro Action. He’s fearless, and also maybe superstrong. “Sounds of Thunder” whiffs toward sending this cerebral fussbudget on a RAMPAGE!!!! He’s talking back to Pike. He’s not afraid of the Ba’ul, even when a Ba’ul chieftain (voiced by Mark Pellington) pustilates its glorposkeletal body ooze through a whispery bad-guy speech.

Saru Goes Bad could be a compelling plotline, maybe. He’s talking about aggressive revolution, starts firing sharptooth daggers out of his gangliatic region. Great Scott, aren’t these the same murderous instincts that made his people tyrants generations ago? But Disco can’t quite own this episode’s best idea. Saru’s rebellious fervor simmers. He promises the Ba’ul a new balance, a diplomatic future where the world’s two halves live in perfect harmony. And then the Ba’ul initiate a genocide device — so much for moral ambiguity.

In Trek historical terms, “Sounds of Thunder” reminds me of “Let That Be Your Last Battlefield,” a famously on-the-nose racism allegory guest-starring Lou Antonio and Frank Gorshin as black-white people. “Battlefield” has a sincere and kinda goofy message about tolerance — and yet, it also has one of the bleakest final acts in the franchise’s history. Disco can do Dark and Violent and Super Serious Guys F’Real, but this show is always chasing a happy ending, a dead lover resurrected, a traitor granted a full pardon.

And “Sounds of Thunder” has a few other major issues, reflecting the overall flaws of this season so far. Discovery goes to Kaminar because the Red Angel leads them there with another space signal. This leads to a brewing internal conflict between Discovery and Section 31. Captain Pike points out that the Red Angel has always led the ship to rescues; Tyler (Shazad Latif) and his black-ops droogs suspect the Red Angel is actually causing these problems.

“Of the billions of planets in our galaxy, the signal just happens to show up above the home world of my first officer,” says Captain Pike. “What are the odds?” I’m beginning to love Mount’s sturdy performance, and he put a deadpan spin on that line. And yet you want to respond to him: “Well, the odds are good when literally the only inciting incident the Disco writing staff can think of anymore is Giant Red Plot Thing Appears in Space.”

And where previous missions used the Red Angel to start a plot, “Sounds of Thunder” wields the mysterious entity as a very plotty Angelus Ruber ex Machina. A moment before genocide, the Angel appears to shut down the Ba’ul’s onslaught, allowing Saru to complete his plan of de-gangliafying his race toward a brighter evolutionary future.

“Who is the Red Angel?” is the question Disco wants us to start asking. But right now, the potential answers are not so intriguing. The hot theory on Discovery is that the creature is staging some sort of chronological incursions, and Saru’s supervision catches sight of a mechanized suit. It’s “a time-traveling being pursuing its own agenda.” So basic plot logic leads you to ponder whether the Red Angel is a character we already know, traveling sideways through the canonscape to nudge themselves toward the midseason finale. (From one angle, the Red Angel’s feet look a bit like the boot portion of the Discovery Starfleet uniform.)

And this is another episode in which Michael’s (Sonequa Martin-Green) only defining characteristic is her relationship with her step-brother. Adding Spock to Disco has been a disaster for Michael’s role in the show, entrapping her in tangled backstory. Perhaps this will change once we finally meet Ethan Peck’s young Vulcan, but we still don’t even know what rifted Michael and Spock, please please please no romance, please. (Now Michael’s jetting off to Vulcan, I guess because it’s been three whole weeks since she’s seen one of her parents, yeesh.)

Still, I like “The Sounds of Thunder” for one simple reason: THERE IS SO MUCH AIRIAM. Multiple lines for Hannah Cheesman’s savvy starbot! “Yes, biosigns were archived by the sphere,” she says, and “The sphere did collect readings from Kaminar. Thousands of years’ worth of statistical measurements.” Airiam is, apparently, a Very Effective Alien Officer, cutting months off the spheroid data dump. Can Airiam be the Red Angel?